Process for bleaching fibers.



ALOIS SCHAIDHAUE, OF FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR TO THE ROESSLER & HASSLAGHER CHEMICAL 00., OF NEW YORK, N. Y., A. CORPORATION OF N EW-YOBK.

No Drawing.

To all whom it may concern:

lie it known that. I, ALois SOIIAIDIL\UF, av subject of the Emperor of Germany, and a resident of Frankfort-on-the Main, Germany, have invented certain new and useful Improvements in Processes for Bleaching Fibers, of which the following is a full, clear, and exact specification.

This invention relates to improvements in processes for bleaching fibers, such as textile fibers for instance, by means of alkaline hydrogen peroxid solutions,

In a copending application Serial No. 7 93,039 filed October 2, 1913, is described an improvement in processes for bleaching fibers by means of alkaline hydrogen peroxid solutions stabilized by anticatalyzers; this last mentioned bleaching process practised by means of oxygen furnished by an alkaline hydrogen peroxid solution, such as is obtained by dissolving sodium peroxid in water, and stabilized by an anticatalyzer, has been carried out up to the present only by heating the bath gradually up to the maximum temperature. In carrying out the process referred to, one preferably heated the bleaching bath at suitable intervals by keeping its temperature at a moderate height for approximately one hour and thereafter raised the temperature to the maximum and exposed the goods at this latter temperature to the action of the bleaching bath for about two hours more. If necessary, the goods were again submitted to the same operations until the desired result was obtained.

The surprising observation has now been made that the preliminary treatment of the goods at a moderate temperature, considered to be absolutely necessary up to now, may be dispensed with, being not always of avail and sometimes being directly unsuitable.

The comparison of results from examples will facilitate the understanding of the invention.

1. If the well known Macco yarn is treated in a bath containing 0.28% sodium peroxid. 0.025% sodium silicate, 0.02% magnesium chlorid and 0.07% Monopol soap for one hour at 65 (3.. and then for two hours more at approximately 87 C., and if the yarn is again subjected to the same operations in a like bath, a white is obtained which is not always equal to that obtained Specification of Letters Patent.

Patented Sept. 10, 1918.

Application filed August 25, 1914. Serial No. 858,575.

if the same yarn is bleached in the usual way with chlorin, V

2. If the same material is treated in a bath of the same composition, but at a tem perature of approximately 87 C. from the very beginning of the operation, the bath being heated to approximately that degree of temperature before goods are innnersed therein, and if the goods are treated for two hours in each of two such baths, for instance, the finished goods are always superior and at the least equal in their whiteness to the same kind of goods bleached in the usual way with chlorin.

In another experiment made for the purpose of comparison in accordance with Ex ample 2, the first bath was drained off after having acted on the goods for only one hour, whereas the treatn'ient in the second bath lasted two hours. Though the bleaching action in this case continued only during three hours yet the white obtained was very much more satisfactory and the strength of material was greater than that of the goods treated by the six hours action of the bath gradually heated as per Example 1.

As to the temperature I have found it advisable to maintain same at approximately 87 C. because beyond that temperature changes of the material of the fiber take place, primarily owing to the action of the hydrogen peroxid-on the cellulose. The result of this reaction is the formation of oxy cellulose whereby the originally soft fiber becomes hardened and then feels harsh and rough.

The new process therefore offers the ad vantage of a considerable saving of time combined with a material improvement in the bleaching effect. This improvement in the bleaching process permits also the bleaching of dark Macco cotton yarn without the necessity of going to any greater expense than in the case of common cotton. This new process is not restricted to the use of baths approximating the composition given above, but may equally well be used in connection with such baths as are stabilized by magnesium compounds or combinations of the same with silica in either the common or, colloidal form as described in the copending applications Serial Nos.

764,738, filed May 1, 1913 and 796,412 filed October 21, 1913, respectively, and furthermore may just as advantageously be used in connection With alkaline bleaching baths stabilized by any other suitable agent acting as such stabilizer, as by organic colloids.

It is obvious that the principle of the invention may as well be applied in connection With the bleaching of other fibers than cotton of the various grades, such as linen, Wood, etc., as also With certain fibers of animal origin and the invention is not restricted to the use of the process in connection with the bleaching of any particular fiber in the bleaching of the various fibers it will of course be understood that changes in the composition of the bath, in the required temperature and in the length of time the goods should be subjected to the bath, may be made Without departing from the spirit of the invention.

What is claimed is 1. The process of bleaching fibers consisting in treating the fiber With alkaline solutions giving of]? oxygen which have been rendered stable by means of anticatalytic substances, said solutions being maintained throughout the treatment at the maximum temperature to which the solution may be heated Without injury to the fibers.

2. The process of bleaching fibers consisting in treating the fibers in a bath of an alkaline solution containing active oxygen in the form of. hydrogen peroxid and an anticatalyte capable of rendering said solution stable and maintaining the bath during the entire bleaching operation, at substantially the maximum temperature to which the solution may be heated Without injury to the fibers.

3. The process of bleaching fibers consisting in treating the fibers in a bath of an alkaline solution containing active oxygen in \the form of hydrogen peroxid and an anticatalyte capable of rendering said solution stable and maintaining the bath at approximately 87 C. during the entire bleaching operation.

4. The process of bleaching fibers consisting in treating the fibers in a bath of an alkaline solution, containing active oxygen and a colloidal combination of magnesia and silica acting as an anticatalyzer, and maintaining the bath at approximately 87 C. during the entire bleaching operation.

5. The process of bleaching fibers consisting in treating the fibers in a bath of an alkaline solution, containing active oxygen in the form of hydrogen peroxid and a col loidal combination of magnesia and silica acting as an anticatalyzer, and maintaining the bath at approximately 87 C. during the entire bleaching operation.

ALOIS SCHAIDHAUF.

WVitnesses I VALETIN WEICKEL, GUSTAV SCHLOSSER. 

